Semiconductor Component Arrangement Comprising a Trench Transistor

ABSTRACT

Disclosed is a semiconductor component arrangement and a method for producing a semiconductor component arrangement. The method comprises producing a trench transistor structure with at least one trench disposed in the semiconductor body and with at least an gate electrode disposed in the at least one trench. An electrode structure is disposed in at least one further trench and comprises at least one electrode. The at least one trench of the transistor structure and the at least one further trench are produced by common process steps. Furthermore, the at least one electrode of the electrode structure and the gate electrode are produced by common process steps.

FIELD

The present invention relates to a method of producing a semiconductorcomponent arrangement comprising a trench transistor and to asemiconductor component arrangement comprising a trench transistor.

BACKGROUND

In order to connect a plurality of components in a semiconductor body orsemiconductor chip to one another to form an integrated circuit or inorder to connect the components integrated in a semiconductor body toterminal contacts for an external interconnection, connection lines alsohave to be produced during the production process for producing of thecomponents.

In known “smart power IC technologies”, that is to say technologieswhich enable a realization of power components, in particular powertransistors, and logic components in one semiconductor chip, often onlytwo wiring levels above one side of the semiconductor body are availablefor the realization of such connection lines or wirings, one of whichlevels comprises metal lines, for example, and the other level compriseslines composed of polysilicon.

If there are a multiplicity of components in the semiconductor body, inparticular a multiplicity of logic components, which are to beinterconnected with one another, space problems may occur. In the caseof such a circuit, it is necessary to interconnect individual logicgates, in particular, and also individual circuit blocks, which may ineach case comprise a plurality of components. What is more, it may benecessary to produce bridgings by means of which two lines of themetallization level that are arranged in a manner spaced apart from oneanother are conductively connected to one another.

Depending on the function of the integrated circuit it may becomenecessary to realize capacitor structures or further electrodestructures in the same semiconductor body as the trench transistor.

SUMMARY

According to one embodiment of the invention, a method for producing asemiconductor component arrangement comprises producing a trenchtransistor structure with at least one trench disposed in thesemiconductor body and with at least an gate electrode disposed in theat least one trench. In addition, an electrode structure is disposed inat least one further trench and comprising at least one electrode. Inthis method, the at least one trench of the transistor structure and theat least one further trench are produced by common process steps, andthe at least one electrode of the electrode structure and the gateelectrode are produced by common process steps.

According to another embodiment of the invention, a semiconductorcomponent arrangement comprises a semiconductor body having a first sideand a second side. A trench transistor structure is integrated in thesemiconductor body and comprises at least one trench and in said trenchat least one gate electrode. At least one electrode structure isdisposed in at least one further trench and comprises at least oneelectrode which in at least one section has the same geometricalstructure as the gate electrode.

In various embodiments, the electrode structure may be part of a wiringstructure/connection line structure or may be part of a capacitorstructure.

Within such a trench it is possible to provide a plurality of separatetrench connection lines which are arranged one above another in thetrench in a vertical direction of the semiconductor body. It goeswithout saying that it is also possible to provide only one trenchconnection line in the trench, which trench connection line may thenhave a cross section of a size in line with the need for realizing alow-resistance line connection.

The trench connection line comprises an arbitrary electricallyconductive material, for example a doped poly-crystalline semiconductormaterial, such as polysilicon, a metal-semiconductor compound, such as,for example, a silicide, or a metal, such as, for example, titanium,tungsten or platinum.

The above-mentioned features and advantages, as well as others, willbecome more readily apparent to those of ordinary skill in the art byreference to the following detailed description and accompanyingdrawings. The teachings disclosed herein extend to those embodimentswhich fall within the scope of the appended claims, regardless ofwhether they include one or more of the above-mentioned features oraccomplish one or more of the above-mentioned advantages.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention are explained in more detail belowwith reference to figures.

FIG. 1 shows a wiring concept for an integrated circuit arrangementaccording to the prior art.

FIG. 2 shows a first exemplary embodiment of a semiconductor componentarrangement comprising a trench line connection.

FIG. 3 shows a semiconductor body with a trench connection line whichconnects two interconnects arranged above a surface of the semiconductorbody to one another.

FIG. 4 shows a cross section through a semiconductor body with twomutually crossing trench connection lines.

FIG. 5 shows a cross section through a semiconductor body in which alateral MOS transistor is realized, the source and drain terminals ofwhich are contact-connected by trench connection lines.

FIG. 6 shows a cross section through a semiconductor body in which avertical trench transistor and a trench connection line are integrated.

FIG. 7 shows a further exemplary embodiment of a component arrangementin which a vertical trench transistor and a trench connection line areintegrated.

FIG. 8 shows a semiconductor body in which a cell array of a powertransistor and a temperature sensor which is contact-connected by atrench connection line and is partly surrounded by the cell array areintegrated.

FIG. 9 illustrates the realization of capacitive structures using thestructures which are used for the realization of trench connectionlines.

FIG. 10 illustrates a method for producing a trench power transistorstructure and a capacitor structure in a common semiconductor body.

FIG. 11 shows a component arrangement comprising a trench powertransistor structure and a capacitor structure which has been producedby means of a modified method by comparison with the method according toFIG. 10.

FIG. 12 illustrates a modification of the method according to FIG. 10.

FIG. 13 shows the result of a modification of the method according toFIG. 12.

FIG. 14 shows the result of a further modification of the methodaccording to FIG. 12.

FIG. 15 shows a further component arrangement comprising a transistorstructure and a capacitor structure.

In the figures, unless specified otherwise, identical reference symbolsdesignate identical component regions with the same meaning.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1A shows a cross section of a component arrangement comprising asemiconductor body 400, on which are arranged two wiring levels, a firstwiring level 420 composed of polysilicon and a second wiring level 410composed of a metal, which are insulated from one another and from thesemiconductor body by insulation layers 431, 432, for example an oxide.“Wiring level” is to be understood hereinafter to mean a layer composedof electrically conductive material which is patterned in such a waythat a plurality of interconnects arranged separately from one anotherare present. The cross section through the metallization level 410 asillustrated in FIG. 1B shows three of such lines 411, 412, 413, whichare arranged in a manner spaced apart from one another and which are ineach case insulated from one another by an insulation material 433arranged in the metallization level. In FIG. 1B, the reference symbol421 designates a polysilicon bridge which conductively connects two 411,412 of the interconnects to one another. Said polysilicon bridge isarranged in the polysilicon level, and thus below the metallizationlevel, and is illustrated in dash-dotted fashion in FIG. 1B. Conductiveconnections between the metal lines 411, 412 and the polysilicon bridge421 are realized by vertically running connections, so-called vias,which in each case extend in a vertical direction through the insulationlayer 432 that isolates the metallization level 420 and the polysiliconlevel 410.

Although the polysilicon used for realizing the polysilicon level 410 ishighly doped, its resistivity is usually higher than the material usedfor the metallization level 420. In order to achieve a connection of thetwo interconnects 411, 412 which has the lowest possible resistance, alargest possible area is required for the polysilicon bridge 421, whichcan therefore lead to space problems if a multiplicity of such“bridgings” have to be realized in the circuit.

FIGS. 2A and 2B illustrate the basic construction of a trench connectionline, which serves, in a manner not specifically illustrated in FIG. 2,for electrically conductively connecting two terminal contacts arrangedin a semiconductor body or on a semiconductor body.

In FIGS. 2A and 2B, the reference symbol 100 designates a semiconductorbody having a first side 101, which is referred to hereinafter as thefront side, and a second side 102, which is referred to hereinafter asthe rear side. The semiconductor body 100 may be realized in any desiredmanner and may have, in particular, a semiconductor substrate 103 and anepitaxial layer 104 applied to the semiconductor substrate, which isillustrated in dashed fashion in FIGS. 2A and 2B.

The semiconductor body 100 has a trench 11 extending into thesemiconductor body 100 proceeding from the front side 101 in a verticaldirection v. FIG. 2A shows said trench in a section B-B transverselywith respect to its extending direction, while FIG. 2B shows the trenchin a section A-A along its extending direction. At least one trenchconnection line 21, 22, 23 is arranged in said trench, said trenchconnection line being insulated from the regions of the semiconductorbody 100 that surround the trench 11 by means of an insulation layer 12.The insulation layer 12 is an arbitrary electrically insulatingdielectric layer, in particular a semiconductor oxide produced by anoxidation method or a deposited semiconductor oxide.

The example shows three trench connection lines 21, 22, 23 which arearranged one above another in the trench 11 in the vertical direction vof the semiconductor body, in each case two adjacent trench connectionlines from among said trench connection lines 21, 22, 23 being insulatedfrom one another by the insulation layer 12.

The individual trench connection lines 21, 22, 23 within the trench 11may be realized such that they are completely isolated from one another.Moreover, referring to FIG. 2B, there is also the possibility of two ofthe trench connection lines, in the example the connections 22, 23,being conductively connected to one another by a vertical connection 23′and, after the connection point, only one of the two connection lines,in the example the connection line 22, being continued in the trench 11in the lateral direction. Such a structure having two connection lines22, 23 which are isolated from one another in sections and continuedjointly starting from a connection point can be used for example forelectrically conductively connecting two terminal contacts (notspecifically illustrated in FIG. 2B) to one another and jointlyconnecting them to a further terminal contact. For this purpose, thesections of the connection lines 22, 23 that are led separately from oneanother are connected to the terminal contacts to be connected and thejointly continued section 22′ of the two connection lines is connectedto the terminal contact to which the other two terminal contacts are tobe electrically conductively connected.

FIGS. 3A and 3B show a cross section (FIG. 3A) and a plan view (FIG. 3B)of a semiconductor body 100, on the front side 101 of which is appliedan insulation layer 103, above which separate interconnects 31, 32, 33are led. Said interconnects comprise for example a metal, for examplealuminum, and may be produced by patterning an interconnect layer—whichis initially applied over the whole area—by means of an etching methodusing etching masks.

Three of such interconnects 31, 32, 33 are present in the illustratedsection of the semiconductor body 100, which interconnects run parallelto one another in sections and the two outer interconnects 31, 33 ofwhich are to be electrically conductively connected to one another. Forthis purpose, a trench connection line 21 is provided, which is arrangedbelow the interconnects in a trench 11 within the semiconductor body 100and which runs transversely with respect to the sections of theinterconnects 31, 32, 33 in which said interconnects run parallel to oneanother. The trench 11 running below the interconnects and having thetrench connection line 21 arranged in it, and the insulation layer 12that insulates the trench connection line 21 from the semiconductor body100 are illustrated in dash-dotted fashion in FIG. 3B.

In the example illustrated, the trench connection line 21 runs in amanner spaced apart from the front side 101 of the semiconductor body100 in the vertical direction, with the result that a section of theinsulation layer 12 is arranged above the trench connection line 21. Inthe example illustrated, in which a further insulation layer 103 thatinsulates the interconnects 31-33 from the semiconductor body is presenton the front side 101 of the semiconductor body, the trench connectionline 21 could also extend as far as the level of the front side 101 ofthe semiconductor body 100 (not illustrated).

Vertical terminal connections 41, 42, which are referred to hereinafteras vias, are provided for connecting the interconnects 31, 33 that areto be connected to one another to the trench connection line 21. Saidvias 41, 42 extend in the vertical direction from the trench connectionline 21 as far as the interconnects 31, 33.

An electrically conductive connection of the interconnects 31, 33 can berealized in a space-saving manner by means of the trench connection line21 since no space above the front side of the semiconductor body 100 isrequired for the trench connection line 21.

The resistance of the connection line 21 is crucially determined by thecross section of the trench connection line 21. Said cross section canbe set in particular by way of the depth of the trench 11, enough spacebeing available in the vertical direction of the semiconductor body torealize a sufficiently large interconnect cross section for the trenchconnection line 21.

Crossovers between two trench connection lines that do not run parallelcan also be realized in a simple manner, as is illustrated in FIGS. 4Aand 4B. FIG. 4A shows a cross section through a semiconductor body 100in a plan view of the front side 101. FIG. 4B shows the semiconductorbody in cross section in a vertical sectional plane D-D illustrated inFIG. 4A. Two trenches 11_1, 11_2 running perpendicular to one anotherare arranged in the semiconductor body, in which trenches trenchconnection lines are in each case realized in different planes. A firstand second trench connection line 21, 22 are realized in the firsttrench, and are arranged in first and second vertical planes, i.e. at afirst and second vertical distance from the front side 101. In a furtherplane different from the first and second planes, a third trenchconnection line 23 is arranged in the second trench 11_2, which thirdtrench connection line crosses the first and second trench connectionlines 21, 22 at the crossover point of the two trenches 11_1, 11_2 in amanner free of contact. The reference symbol 24 designates a furthertrench connection line in the first trench 11_1, which further trenchline connection, within said trench 11_1, does not, however, extendbeyond the crossover point of the trenches 11_1, 11_2, but rather isconnected to the second trench connection line 22 via a verticalconnection 24 before the crossover point.

The trench connection lines according to the invention are also suitablefor contact-connecting active component zones of semiconductorcomponents arranged in a semiconductor body 100, as is explained belowwith reference to FIGS. 5A and 5B. In this case, FIG. 5A shows thesemiconductor body 100 in side view in cross section, while FIG. 5Billustrates a lateral cross section through the sectional plane E-Edepicted in FIG. 5A. In this exemplary embodiment, a lateral MOSFET isintegrated in the semiconductor body 100, said lateral MOSFET having asource zone 51 of a first conduction type, a drain zone 54 arranged in amanner spaced apart from the source zone 51 in the lateral direction, adrift zone 53, which adjoins the drain zone 54 and is doped more weaklythan the drain zone 54, and also a body zone 52, which is arrangedbetween the drift zone 53 and the source zone 51 and is dopedcomplementarily with respect to the source zone 51. In order to controlan inversion channel in the body zone 52 between the source zone 51 andthe drift zone 53, a gate electrode 55 is present, which is insulatedfrom the semiconductor body 100 by a gate insulation 56. In the example,said gate electrode 55 is arranged above the front side 101 of thesemiconductor body. In the lateral MOS transistor illustrated, the driftzone 53 serves for increasing the dielectric strength of the component.In the case of logic components, in which only a low dielectric strengthis required, said drift zone can be dispensed with, if appropriate.

In the case of this component, the source and drain zones 51, 54 arerespectively contact-connected by trench connection lines 21, 25. Saidtrench connection lines are respectively arranged in trenches 11, 14 andelectrically conductively connected to the source and drain zones 51, 54via terminal connections 41, 45. Moreover, the trench connection linesare insulated from the semiconductor body 100 by means of insulationlayers 12, 13. In addition, a further insulation layer is present, whichcovers the trench connection lines 21, 25 in the direction of the frontside 101 in order to insulate the trench connection line for examplefrom further interconnects (not illustrated) which may be arranged abovethe front side 101.

The trench connection lines 21, 22 serve for example for connecting thesource and drain zones 51, 54 to active component zones of furthercomponents (not illustrated) integrated in the semiconductor body, inorder thereby to realize an integrated circuit whose wiring does notrequire any space above the semiconductor body. Furthermore, there isalso the possibility of leading the trench connection lines to the frontside in a manner spaced apart from the source and drain zones 51, 54contact-connecting them, in order to connect them, at said front side,to an external terminal potential via terminal contacts, as isillustrated for the trench connection line 21 in FIG. 5 c.

The trench connection lines described above at least partially may beproduced by the same process steps as the gate electrode of a trenchpower transistor integrated in the semiconductor body. This will beexplained below with reference to FIGS. 6 and 7.

FIG. 6 shows in side view a semiconductor body 100, in which areintegrated a transistor structure of a vertical trench power transistor60 and trench connection lines 21, 22, 23 for the wiring of logiccomponents that are not specifically illustrated and are likewiserealized in the semiconductor body 100. The transistor structure 60 isconstructed in cellular fashion and comprises a number of in each caseidentical transistor cells. Each transistor cell comprises, in thevertical direction of the semiconductor body 100, proceeding from thefront side 101, a source zone 61 of a first conduction type, a body zone62 of a second conduction type complementary to the first conductiontype, a drift zone 63 of the first conduction type, and also a drainzone 69 of the first conduction type, which is doped more highly thanthe drift zone 63. In order to realize a MOSFET, the drain zone 69 isdoped complementarily with respect to the body zone 62, while the drainzone 69 is doped complementarily with respect to the drift zone 63 inorder to realize an IGBT.

In order to control an inversion channel in the body zone 62 between thesource zone 61 and the drift zone 63, a gate electrode 64 is present,which is arranged in a trench extending into the semiconductor body inthe vertical direction proceeding from the front side 101. Said gateelectrode 64 is insulated from the body zone 62 by means of a gateinsulation layer 65. Two field electrodes 66, 67 are present in thetrench below the gate electrode 64, said field electrodes beinginsulated from the drift zone 63 by means of a field plate insulationlayer 68.

In the present case, the semiconductor body 100 comprises a highly dopedsemiconductor substrate 103, which forms the drain zone 69, and also amore weakly doped epitaxial layer 104, which is applied to thesemiconductor substrate 103 and which forms the drift zone 63 insections and in which the source and body zones 61, 62 are realized inthe region of the front side 101. The transistor structure illustratedin the left-hand part in FIG. 6 is known in principle and described inDE 103 39 455 C1, which is incorporated herein by reference.

The gate electrode 64 and the field electrodes 66, 67 are produced in aknown manner by etching a trench starting from the front side of thesemiconductor body 100, by producing a dielectric layer on sidewalls ofthe trench and by depositing of electrode layers, which form the fieldelectrodes 66, 67 and the gate electrode 64. For the arrangement of FIG.6 first the lower (second) field electrode 67 is produced by depositinga first electrode layer. This electrode layer may be etched back in avertical direction in order to adjust the dimension of the lower fieldelectrode in the vertical direction. Subsequently a dielectric layer isproduced on the lower field electrode 67, for example, by depositing adielectric or by partially oxidizing the lower field electrode 67. In acorresponding manner the upper (first) field electrode 66 and the gateelectrode 64 may be produced. By means of the same process steps whichare used for producing the gate electrode 64 and the field electrodes66, 67 in the trenches of the transistor structure, at least parts ofthe trench wiring or the trench connection lines are produced, namelythose parts of the trench wiring which—corresponding to the fieldelectrodes 66, 67 and the gate electrode 64—extend in a lateraldirection of the semiconductor body 11 and therefore run parallel to thefront side 101.

The body zones 62, as well as the source zones 61 and the connectingzones 70 may be produced before or after producing the trench structureswith the gate and field electrodes 64, 66, 67 and the connection lines21, 22, 23. These semiconductor zones may be produced by implantationand/or diffusion of dopants into the semiconductor layer 104.

Those section of the trench connection lines, which extend in a verticaldirection 100 of the semiconductor body, and which therefore runperpendicular to the front side 101, may be produced by simplemodifications of the method discussed above. Such a section runningperpendicular to the surface, for example, is the section 23′ of FIG.2B, which connects two lines 22, 23 which are parallel to one another.Such connection may be produced by removing a dielectric separating thelines 22, 23 in an area, in which the connection 23′ is to be produced,before an electrode layer for producing the second connection line 22 isdeposited. Alternatively, producing a dielectric in the area of thisconnection 23′ may be prevented after an electrode layer forming thelower line 22 has been deposited.

The aforementioned DE 103 39 455 C1 describes connecting the individualfield electrodes of the transistor structure to different electricalpotentials. In the case of the arrangement illustrated in FIG. 6, thefield electrodes 66, 67 can be connected, in a manner not specificallyillustrated, via trench connection lines to suitable potential sourcesthat provide the desired different potentials. Said potentials may begenerated for example using a Zener diode chain comprising a pluralityof series-connected Zener diodes across which a supply voltage ispresent. In this case, different potentials can be tapped off atintermediate taps of the Zener diode chain, that is to say at connectionpoints of in each case two Zener diodes directly connected in series.

The source zones 61 of the transistor structure are jointly connected toa source electrode 71, which also makes contact with the body zone 62via highly doped terminal zones 71 in order thereby to short-circuitsource and body in a known manner. In the logic portion, for whichtrench connection lines 21, 22, 23 are illustrated in a representativemanner in FIG. 6, there is the possibility of arranging interconnectsabove the front side 101 of the semiconductor body in accordance withFIGS. 3A and 3B.

FIG. 7 shows a further semiconductor component arrangement, in which atrench transistor structure and trench connection lines are integratedin a common semiconductor body 100. The trench power transistorstructure illustrated in FIG. 7 is known in principle from DE 100 63 443A1 and differs from that illustrated in FIG. 6 by virtue of the factthat an electrode 64A is present, which, in the upper region of thetrench, that is to say in the region of the body zone 62, is insufatedfrom the body zone 62 by a gate insulation layer 65, which is thin incomparison with a field plate dielectric 68, and acts as a gateelectrode there, while in the lower region of the trench it is insulatedfrom the drift zone 63 by the thicker field plate dielectric 68 and actsas a field plate 64B there. In the upper region of the trench, the gateelectrode has a forked structure enclosing a further electrode section64C in the lateral direction, said further electrode section usuallyalso being connected to gate potential.

In the example illustrated, the drain zone 69 of the transistorstructure 60 is realized as a buried highly doped zone which is led tothe front side 101 at the edge of the cell array comprising theindividual transistor cells of the transistor structure.

The method for producing this gate electrode formed in forked fashionwith the further electrode 72 enclosing it can be used correspondinglyfor realizing at least parts of two trench connection lines 21, 22 thatare electrically insulated from one another, and that are arranged in afurther trench 11 which is spaced apart from the trench transistorstructure 60. The method, in particular, is suitable for producing thoseparts of the connection lines 21, 22 that run parallel to the front sideof the semiconductor body.

In the component structures of FIGS. 6 and 7 the trench transistorstructure besides a gate electrode 64 comprises a field electrode, whichtogether with the gate electrode 64 is disposed in a common trench. Thetrench connection lines disclosed in these figures comprise a number oflines which corresponds to the number of gate and field electrodes ofthe transistor structure. It should be mentioned in this connection thatthe transistor structure not necessarily comprises a field electrode.Thus, only a gate electrode may be produced. In this case the trenchwiring comprises only one line.

Furthermore, the number of parallel trench connection lines may be lowerthan the number of electrodes of the transistor structure. In this casethe method is modified in such a manner that an area of thesemiconductor body 100, in which the trench wiring is produced, ismasked during deposition of at least one of the electrode layers formingthe electrodes. Alternatively, the method is modified in such a mannerthat one of the deposited electrode layers is removed in this area.

A method in which at the same time with producing an electrode structure64-66 in a transistor trench of a semiconductor body 100 at least partsof a trench wiring structure 21-23 is produced, results to a componentstructure which comprises connection lines, that at least partially orin sections have identical geometrical structures as the electrodestructure 64-66 of the transistor. The connection lines may be comprisedof the same material as the electrodes 64-66 of the transistor and maybe insulated by the same dielectric material against one another andagainst the semiconductor material of the semiconductor body 100. Theelectrodes 64-66 and the connection lines 21-23, for example, arecomprised of a doped polysilicon of the same doping concentration.

A further possible application of the trench connection lines explainedabove is explained below with reference to FIGS. 8A to 8C. FIG. 8A showsin plan view a semiconductor body 100, in which a cell array comprisingtransistor cells constructed identically in each case is realized. Saidtransistor cells may be for example transistor cells in accordance withFIGS. 6 and 7 or arbitrary further transistor cells. A temperaturesensor 80 is present in a manner surrounded by the transistor cells ofsaid transistor cell array, said temperature sensor serving fordetecting the temperature within the cell array. With regard to atemperature measurement that is as exact as possible, it is desirable inthis case for the temperature sensor 80 to be surrounded as completelyas possible by the transistor cells of the cell array in the lateraldirection of the semiconductor body 100. In this context, it isnecessary to avoid wide connection lines at the surface of thesemiconductor body since no transistor cells can be realized below saidconnection lines. The trench connection lines explained above make itpossible to realize a space-saving line routing to the temperaturesensor 80. FIG. 8B shows said trench connection lines 21, 22 in crosssection, each of said connection lines respectively contact-connectingone of two terminal contacts of the temperature sensor 80.

Referring to FIG. 8C, the temperature sensor 80 is realized for exampleas a pn junction with an n-doped zone 81 and a p-doped zone 82, said pnjunction being operated in the reverse direction. This makes use of thefact that the reverse current of such a reverse-biased pn junctionraises exponentially with the temperature. The upper one of the trenchconnection lines 21, 22 arranged in the trench 100 makes contact withthe n-type zone 81, for example, while the lower one makes contact withthe p-type zone 82 of the temperature sensor 80.

The trench connection lines discussed above which, at least partially,are produced by the same process steps as an electrode structure of atrench transistor may also serve as capacitive structures within thesemiconductor body 100, as will be explained in the following.

FIG. 9A shows a cross section through a semiconductor body 100 having atrench 11 with trench connection lines 21-23 arranged therein. In eachcase two adjacent trench connection lines from among said trenchconnection lines form a capacitor electrode of a capacitor.

This presupposes that the two adjacent trench connection lines are ineach case electrically contact-connected only at one side, while theother side of the connection line remains open. This is illustrated inside view in cross section in FIG. 9B. In this example, the trenchconnection lines in each case end within the trench 11, while theirother ends are led to the front side 101 in order to becontact-connected there. The capacitor dielectric is formed by theinsulation layer or dielectric layer 12 arranged between the individualtrench connection lines 21-23 within the trench 11.

The circuit symbols of the capacitors formed by in each case twoadjacent trench connection lines are likewise depicted in FIG. 9A.

What is more, there is also the possibility of using a semiconductorregion 91 surrounding the trench, which semiconductor region ispreferably doped complementarily to a basic doping of the semiconductorbody 100, as a capacitor electrode and of using the trench connectionlines 21, 22, 23 in each case as other capacitor electrode, said trenchconnection lines optionally being connected to a common electricalpotential in order to realize a capacitive structure having aparticularly high capacitance. In FIG. 9A, the reference symbol 92designates a terminal of the semiconductor region 91 that surrounds thetrench and forms a capacitor electrode.

What is more, there is also the possibility of realizing a plurality ofseparate capacitors by connecting the individual trench connection lines21-23 to separate electrical potentials.

A particularly effective method for realizing a power transistorstructure and a capacitor structure in a common semiconductor body, inwhich largely common method steps are used for producing the powertransistor structure and the capacitor structure, is explained belowwith reference to FIGS. 10A to 10E.

FIG. 10A shows in side view a cross section through a semiconductor body200 having a first side 201, which is referred to hereinafter as thefront side, and a second side 202, which is referred to hereinafter asthe rear side.

In the example, the semiconductor body 200 comprises a semiconductorsubstrate 205 and an epitaxial layer 206 applied to the semiconductorsubstrate 205. In FIG. 10A, the reference symbol 203 designates asection of the semiconductor body in which a transistor structure isintended to be realized, and the reference symbol 204 designates asection of the semiconductor body 200 in which a capacitor structure isintended to be realized. Said sections 203, 204 are referred tohereinafter as transistor section and capacitor section of thesemiconductor body 200.

FIG. 10A shows the semiconductor body 200 after first method stepsinvolving the production of trenches 211, 212 in the region of thetransistor section 203 and trenches in the region of the capacitorsection 204. Said trenches 211, 212 are referred to hereinafter astransistor trenches 211 and capacitor trenches 212.

Said trenches 211, 212 are produced in a known manner by applying apatterned etching mask 300 to the front side 101, for example an oxidehard mask, and subsequently etching the semiconductor body 200 in theregions in which the etching mask 300 has cutouts which define thetrenches. In this case, the dimensions of the trenches 211, 212 in alateral direction of the semiconductor body 200 are dependent on thedimensions of the openings of the etching mask 300.

The trenches 211, 212, running in elongated fashion in a directionperpendicular to the plane of the drawing illustrated in FIG. 10A, canbe produced in such a way that the transistor trenches 211 have a widthidentical to that of the capacitor trenches 212, but the trenches 211,212 may also have different widths. Said trenches 211, 212 arepreferably produced in such a way that the capacitor trenches 212 arewider than the transistor trenches 211. In this case, the “width”denotes the dimensions of the trenches 211, 212 transversely withrespect to their longitudinal direction.

The transistor and capacitor trenches 211, 212 may furthermore also havedifferent depths, that is to say different dimensions in a verticaldirection of the semiconductor body 200. When carrying out ananisotropic etching method for producing the trenches 211, 212, thedepth of the latter can be set by way of the width of the cutouts in theetching mask. For a given etching duration, the trench depth is all thegreater, the wider the cutouts. However, the transistor trenches andcapacitor trenches 211, 212 formed with this method have the samegeometry or the same geometrical basic structure in a vertical sectionplane. The geometry of one trench is, for example, defined by a ratiobetween the depth and the width of the trench, an angle between thesidewalls of the trenches and a vertical direction, etc.

The transistor trenches 211 can be implemented as longitudinal trencheswhich each have a length in a direction perpendicular to the sectionplane illustrated in FIG. 10A. According to one embodiment, a length ofthe transistor trenches 211 is at least 10 times of their width. Thewidth of the transistor trenches 211 is their dimension in the lateraldirection of the semiconductor body 200 in the section plane illustratedin FIG. 10B. According to one embodiment, the capacitor trenches 212 arealso implemented as longitudinal trenches which have a length which isat least 10 times their widths. In the horizontal plane—which is a planeperpendicular to the section plane illustrated in FIG. 10A—longitudinaltrenches have a rectangular geometry with a length-to-width ratio of atleast 10.

According to another embodiment the capacitor trenches have a polygonalshape with a width and a length in the horizontal plane, the length ofthe capacitor trenches 212 being smaller than 10 times of their width.

According to another embodiment, the capacitor trenches 212 are notimplemented as longitudinal trenches, but are implemented as pile-shapedtrenches. In the horizontal plane, these trenches may have a squaregeometry, a hexagonal geometry, an octagonal geometry, or a circulargeometry. Nevertheless, there is one vertical section plane—like thesection plane illustrated in FIG. 10A—in which these trenches have thesame geometry.

FIG. 10B shows the semiconductor body 200 after further method stepsinvolving the production of a dielectric layer 221 in the capacitortrenches 212 and on the front side 201 of the capacitor section 204.Said dielectric layer 221 is an oxide layer, for example, which isproduced after the removal of the etching mask (reference symbol 300 inFIG. 10A) by thermal oxidation of uncovered areas of the capacitorsection 204, that is to say the front side of the semiconductor body 200in said capacitor section 204 and the sidewalls of the trenches 212.Said oxidation layer 221 grows onto the semiconductor body in thecapacitor section 204, semiconductor materials “being consumed”. Thedash-dotted line in FIG. 10B shows the course of the surface of thecapacitor section 204 before the thermal oxidation for the production ofthe dielectric layer 221.

Before the thermal oxidation of the capacitor section 204 is carriedout, an oxidation protection layer 230 is applied to uncovered surfaceregions of the transistor section 203, which layer prevents theproduction of an oxidation layer on the surface of the semiconductorbody 200 in the transistor section 203. Said oxidation protection layer230 is a nitride layer, for example.

FIG. 10C shows the semiconductor body 200 in cross section after furthermethod steps involving the removal of the oxidation protection layer 230and the production of a gate dielectric layer 241 at the sidewalls ofthe transistor trenches 211. Said gate dielectric layer is an oxidelayer, for example, which is produced by means of a thermal oxidation,the oxidation conditions being set such that the gate insulation layeris thinner than the capacitor dielectric layer 221 of the capacitorsection 204. On account of the oxidation of the semiconductor body inthe transistor section, an insulation layer also arises above the frontside 201 of the semiconductor body, which is removed again in a latermethod step.

It should be noted, that the dielectric layer 221 and the gatedielectric 231 can be produced from dielectric materials other than anoxide as well. According to a further embodiment, at least one of thedielectric layer 221 and the gate dielectric 231 includes a layer stackwith at least two different dielectric layers. According to oneembodiment, the layer stack is an ONO-stack including an oxide (O)layer, a nitride (N) layer and an oxide (O) layer, arranged in the orderas mentioned.

In further method steps, the result of which is illustrated in FIG. 10D,an electrode layer 222, 232 is jointly deposited onto the capacitorsection 204 and the transistor section 203. Said electrode layer forms acapacitor electrode 222 in the capacitor section 204 and the later gateelectrode of the power transistor structure in the transistor section.

The capacitor structure is completed after these method steps. Saidcapacitor structure is formed by the capacitor electrode 222, thecapacitor dielectric 221 and a semiconductor zone 223 surrounding thetrenches with the capacitor dielectric 221. Said semiconductor zone 223is for example doped complementarily with respect to the semiconductorsubstrate 205 and doped complementarily with respect to the epitaxiallayer 206 in the region of the transistor structure 203. The capacitorelectrode 222 has a geometry which corresponds to or is defined by thegeometry of the capacitor trench 212, so that the capacitor electrode222 basically has the same geometry as the capacitor trench 212.

The epitaxial layer 206 forms the later drift zone of the component insections in the region of the transistor structure. A complementarydoping of the drift zone and the semiconductor zone 223 that forms asecond capacitor electrode avoids shunt currents between these componentregions within the semiconductor body 200.

FIG. 10E shows the semiconductor body 200 in cross section after theperformance of further method steps known in principle for completingthe transistor structure after the production of the trenches, the gateinsulation layer 231 and the gate electrodes 232. Said method stepscomprise the removal of the electrode layer 232 from the front side 201of the semiconductor body 200 in the region of the transistor trenches.Said removal may be effected by means of an etching method, by way ofexample. In this case, said electrode layer is preferably etched back toan extent such that the gate electrodes 232 end below the front side 201of the semiconductor body in the trenches 212.

The gate electrode 232 of the transistor structure and those parts ofthe capacitor electrode 222 arranged in the trenches basically have thesame geometry or geometrical basic structure, because of the samegeometry of the transistor trenches 211, on the one hand, and thecapacitor trenches, on the other hand. The same geometries of thetransistor trenches 211 and the capacitor trenches 211 can be obtainedby producing the transistor trenches 211 and the capacitor trenches 212by the same/common method steps. These common method steps may includeforming the etch mask 300 (see FIG. 10A) on the semiconductor body 100and etching the semiconductor body 100 in openings of the etch mask,wherein these openings do not need to have the same sizes.

It should be noted that the method for producing the gate electrodes 232and the capacitor electrode 222 is not restricted to produce thetransistor trenches 211 and the capacitor trenches 212 by common methodsteps and to also produce the gate electrodes 232 and the capacitorelectrode 222 by common method steps.

According to one embodiment, the transistor trenches 211 and thecapacitor trenches 212 are formed by common method steps, but the gateelectrodes 231 and the capacitor electrode 222 are formed by differentmethod steps. “Forming by different method steps” in this connectionmeans, that there is no common process, like a deposition process, whichforms the gate electrodes 232 and the capacitor electrode 222.

According to another embodiment, the transistor trenches 211 and thecapacitor trenches 212 are not formed by common method steps, but thegate electrodes 231 and the capacitor electrode 222 are formed by commonmethod steps. These common steps may include a common depositionprocess, like a deposition process as illustrated in FIG. 10D.

Referring to FIG. 10E, the production of the transistor structureadditionally comprises the production of a body zone 233 dopedcomplementarily with respect to a basic doping of the epitaxial layer206, and also the production of source zones 234 which are dopedcomplementarily with respect to said body zone 233 and which adjoin thetrenches with the gate electrode 232 in a known manner. Moreover, asource electrode 236 is produced, which makes contact with the sourcezones 234 and is insulated from the gate electrodes 232 by furtherinsulation layers 237 above the gate electrodes 232. The sourceelectrode 236 can also make contact with the body zone 233 in a knownmanner in order to short-circuit source 234 and body 233.

The transistor structure has a cell structure comprising a multiplicityof identically constructed transistor cells each having a gate electrode232 arranged in a transistor trench. In this context it should bepointed out that the electrode layer can remain, in an edge region ofthe cell array, above the front side of the semiconductor body 200 in amanner that is not specifically illustrated.

The electrical equivalent circuit diagram of the power transistor islikewise illustrated in FIG. 10E. The drain zone of said powertransistor is formed by the semiconductor substrate 205. The powertransistor illustrated in FIG. 10E is realized as an n-channel MOSFET.Said transistor may, of course, also be realized as a power IGBT, inwhich case the semiconductor substrate is to be realized complementarilywith respect to the epitaxial layer that forms the drift zone 235.

FIG. 11 shows a component arrangement comprising a power transistorstructure and a capacitor structure in a common semiconductor body 200,which is produced by means of a modified method by comparison with themethod according to FIG. 10. In this method, the electrode layer 222 isalso etched back to below the upper edge of the dielectric layer 221 inthe region of the capacitor structure, whereby separate electrodesections 222A, 222B are produced in the individual trenches. A pluralityof separate capacitors which have a common capacitor electrode with thesemiconductor zone 223 can be realized as a result.

FIGS. 12A to 12C illustrate a modification of the method explained abovewith reference to FIG. 10. Referring to FIG. 12A, in this method, afterthe production of the transistor and capacitor trenches 211, 212,firstly the gate insulation layer 231 is produced, as a result of whichan insulation layer 224 is also produced on the front side 201 and inthe capacitor trenches of the capacitor section 204.

Referring to FIG. 12B, the electrode layer 232 is subsequentlydeposited, which forms the later gate electrodes in the transistorsection. In the transistor section, said electrode layer protects thegate insulation layer during subsequent method steps for producing thecapacitor dielectric in the capacitor section.

FIG. 12C shows the semiconductor body after the production of saidcapacitor dielectric 221 and an electrode 225 applied to the capacitordielectric 221, a function of said electrode corresponding to theelectrode 222 in accordance with FIG. 10E. The production of thecapacitor dielectric 221 is preceded by the removal of the insulationlayers 224 and the electrode layer 232 in the region of the capacitorstructure. The production of the capacitor dielectric 221 may beeffected in the manner explained by a thermal oxidation or else bydeposition of an oxide layer, such as, for example, TEOS layer (TEOS=tetraethoxysilane). After the production of the capacitor dielectric221, the electrode layer 225 is deposited in a conventional manner. Thecapacitor structure is completed after the conclusion of these methodsteps.

It goes without saying that, in accordance with the exemplary embodimentin FIG. 11, there is also the possibility of subdividing this capacitorelectrode in order to realize a plurality of capacitors in the capacitorsection 204.

The further method steps for completing the transistor structureproceeding from the structure in accordance with FIG. 12C correspond tothe method steps explained with reference to FIG. 10E.

FIG. 13 shows as the result a component structure in which the gatedielectric layer 231 and the capacitor dielectric 224 are produced bythe same method steps. Such a component may be obtained, proceeding fromthe method according to FIG. 12, by virtue of the fact that the methodsteps explained with reference to FIG. 12, involving the production ofthe gate dielectric 231 in the transistor trenches 211 and theinsulation layer 224 in the capacitor trenches by means of common methodsteps, and involving the production of electrode layers 232, 222 in thetransistor and capacitor trenches 211, 212 by means of further commonmethod steps, are followed directly by the method steps explained withreference to FIG. 10E for completing the transistor structure. In thiscomponent, the insulation layer produced during the production of thegate dielectric 231 in the transistor trenches forms the capacitordielectric, and the electrode 222 produced during the production of thegate electrode 232 forms one of the capacitor electrodes. Said electrode222 may be maintained as a one-piece electrode, as is illustrated inFIG. 13.

Referring to FIG. 14, there is furthermore the possibility of etchingback said electrode 222 in such a way that individual electrodes arisein the capacitor trenches 212 in order thereby to realize a number ofindividual capacitors. In this case, the semiconductor region 223surrounding the trenches forms a common electrode for the individualcapacitors. In the component in accordance with FIG. 14, saidsemiconductor region 223 is contact-connected by a further electrode227, which is arranged above the semiconductor body 200 and which isinsulated from the electrodes 222 arranged in the trenches in a regionabove the semiconductor body 200 by means of insulation layers 228.

The methods of FIGS. 10 to 14 result to component arrangements having atrench transistor structure and a capacitor structure, with thecapacitor structure comprising at least one capacitor electrode disposedin a trench and having at least partially the same geometrical basicstructure as the electrode structure of the transistor. “Samegeometrical basic structure” in this connection means, that thegeometrical structures in general are the same but may vary in terms oftheir lateral or vertical dimensions. The materials of the electrodestructure of the transistor and the materials of the electrode structureof the capacitor are identical.

FIG. 15 shows a vertical cross section through a further componentarrangement having a transistor structure and a capacitor structure. Inthis case, the transistor structure corresponds to the transistorstructure already explained with reference to FIG. 7 and comprises anumber of transistor cells having gate electrodes 64 arranged intrenches, which merges into a field plate 64B in the vertical directionof the semiconductor body and which encloses a further electrode section64C in forked fashion.

The capacitor structure has capacitor electrodes which are arranged intrenches and whose geometry corresponds to that of the gate electrodes64A, field plates 64B and electrode sections of the transistor structureand which are designated by the reference symbols 241, 242, 243 in FIG.15. Depending on the contact-connection of the individual electrodes,different capacitors can be formed by this arrangement. If the forkedelectrodes 241, 242 and the electrode 243 surrounded by the latter arecontact-connected separately, then a respective capacitor is formed byeach of said forked electrodes 241, 242, by the electrode 243 surroundedby the latter, and by the intervening dielectric.

The trenches with the electrodes 241, 242, 243 are surrounded, in theexample, by a semiconductor zone 223 doped complementarily with respectto a basic doping of the semiconductor body 200 and in the examplecomplementarily with respect to the drift zone 63 of the transistorstructure. Said semiconductor zone 223 can be contact-connected via ahighly doped terminal zone 226 and forms a capacitor electrode. In thisarrangement, a capacitor is formed by the semiconductor zone 223, adielectric 244 arranged in the trenches, and also the forked electrode241, 242.

The electrode structure produced in trenches together with the electrodestructure of the trench transistor—as explained above—at least partiallymay be used as a wiring structure or as an electrode structure of acapacitor. However, such electrode structure is not limited to this use.

While the invention disclosed herein has been described in terms ofseveral preferred embodiments, there are numerous alterations,permutations, and equivalents which fall within the scope of thisinvention. It should also be noted that there are many alternative waysof implementing the methods and compositions of the present invention,It is therefore intended that the following appended claims beinterpreted as including all such alterations, permutations andequivalents as fall within the true spirit and scope of the presentinvention.

1. A method for producing a semiconductor component arrangement, themethod comprising: producing a trench transistor structure including atleast one trench disposed in the semiconductor body and at least onegate electrode disposed in the at least one trench; producing anelectrode structure disposed in at least one further trench, theelectrode structure comprising at least one electrode; wherein the atleast one trench of the transistor structure and the at least onefurther trench are produced by common process steps; and/or wherein thegate electrode and the at least one electrode of the electrode structureare produced by common process steps.
 2. The method of claim 1, whereinthe at least one trench of the transistor structure and the at least onefurther trench are produced by common process steps; and wherein thegate electrode and the at least one electrode of the electrode structureare produced by common process steps.
 3. The method of claim 1, furthercomprising: producing at least one field electrode of the trenchtransistor structure in the at least one trench; producing the electrodestructure to comprise at least two electrodes; wherein the at least twoelectrodes of the electrode structure and the at least one gateelectrode and the at least one field electrode are produced by commonprocess steps.
 4. The method of claim 1, wherein the at least one trenchof the trench transistor structure and the at least one further trenchare produced having different trench widths.
 5. The method of claim 1,wherein prior to producing the at least one gate electrode of the trenchtransistor structure and prior to producing the at least on electrode ofthe electrode structure, dielectric layers are produced on surfaces ofthe at least one trench of the trench transistor structure and the atleast one further trench.
 6. The method of claim 1, wherein the trenchtransistor structure comprises a body zone and a source zone which areadjacent to the at least one trench of the trench transistor structure,wherein the body zone and the source zone are produced after producingthe at least one gate electrode.
 7. The method of claim 1, wherein theelectrode structure is part of a trench wiring structure.
 8. The methodof claim 1, wherein the electrode structure is part of a capacitorstructure.
 9. The method of claim 1, wherein a gate dielectric isproduced on surfaces of the at least one trench of the trench transistorstructure, and wherein a capacitor dielectric is produced on surfaces ofthe at least one further trench.
 10. The method of claim 9, whereinproducing the capacitor dielectric comprises the steps of thermallyoxidizing surfaces of the at least one further trench, and protectingthe trench transistor structure against an oxidation by a protectionlayer during said thermal oxidation step.
 11. The method of claim 10,wherein the gate dielectric is produced after the removal of theprotection layer.